Jean Jouzel is a world-renowned paleoclimatologist and from 2002 to 2015 was Vice-Chairman of the Scientific Committee of the Intergovernmental Panel on Climate Change (IPCC). Recipient of numerous scientific awards, he received, in 2002 with Claude Lorius, the CNRS Gold Medal and, in 2012 with Susan Salomon, the Vetlesen Prize, the Earth and Universe Sciences Prize, considered to be the equivalent of the Nobel Prize for these fields. Today, the Covid-19 pandemic and its health, but also economic and social consequences, give him hope that the future recovery will be greener and provide the opportunity to invent a more sustainable development model. Portrait of a man of commitments.